Processes Controlling Transfer of Fine-Grained Sediment in Tidal Systems Spanning a Range of Fluvial Influence
Abstract
A long-term goal of our sediment transport and deposition investigations is to link sediment-transport processes to the formation and preservation of event beds in sediment deposits. The general aim of this project is to investigate how forcing processes affect the sediment-transport dynamics that act to import or export fine-grained sediment in shallow-water regions with fine-grained sediment supply. We strive to understand how the delicate balance of ebb and flood sediment fluxes is maintained to create tidal flat and mangrove complexes, and distributary shoals and islands within tidal rivers. All of these environments are characterized by variable bathymetry and variable seabed stability, and our goal is to answer the question: How do the processes that control the transfer of fine-grained sediment, e.g., tidal (semidiurnal, fortnightly), riverine and other seasonal (winds/waves, precipitation temperature, and biological) processes influence the transport pathways, seabed erosion/deposition, and morphological development in shallow tidal systems? Understanding the transfer and transformation of sediment between terrestrial source and marine sink is essential for knowledge of global carbon budgets, landform evolution, and interpreting the stratigraphic record. Sediment is eroded, transported, and trapped via a myriad of processes along the continuum from terrestrial to oceanic environments. These processes are driven by the varying degrees of fluvial, wave, and tidal influence in each environment. At present, we are completing our studies on unvegetated tidal flats, and are ramping up our focus on sedimentary phenomena in relatively unstudied components within the source-to-sink framework: the connection between the tidal river and the subaqueous delta on the inner continental shelf, and sediment sinks within vegetated/mangrove shoreline complexes. Our overall hypothesis is that sediment-transport signals (magnitude, grain size, pathways) are modulated.
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 30, 2012
- Accession Number
- ADA572944
Entities
People
- A. S. Ogston
Organizations
- University of Washington